Children ages 7-18 and adults with Tourette's Syndrome (TS), Obsessive Compulsive Disorder (OCD) and Attention Deficit Hyperactivity Disorder (ADHD) are being studied for orienting response, alpha asymmetry, evoked response potential, and acoustic startle. From this group some of the subjects will have quantitative EEG analyses performed. Age and sex-matched controls are being used in this study.